JPWO2018062405A1 - Cured body and multilayer substrate - Google Patents

Abstract

Provided is a cured body that can improve the adhesion between an insulating layer and a metal layer and reduce the surface roughness of the surface of the insulating layer. The cured body according to the present invention is a cured body of a resin composition containing an epoxy compound, a curing agent, an inorganic filler, and polyimide, and the content of the inorganic filler is 30% by weight in 100% by weight of the cured body. As mentioned above, it is 90 weight% or less, the said hardening body has a sea island structure which has a sea part and an island part, the average major axis of the said island part is 5 micrometers or less, and the said island part contains the said polyimide.

Description

  The present invention relates to a cured body using a resin composition containing an epoxy compound, a curing agent, and polyimide. Moreover, this invention relates to the multilayer substrate using the said hardening body.

  Conventionally, various resin compositions have been used to obtain electronic components such as laminates and printed wiring boards. For example, in a multilayer printed wiring board, a resin composition is used in order to form an insulating layer for insulating inner layers or to form an insulating layer located in a surface layer portion. On the surface of the insulating layer, a wiring generally made of metal is laminated. Moreover, in order to form an insulating layer, the B stage film which made the said resin composition into a film may be used. The resin composition and the B stage film are used as insulating materials for printed wiring boards including build-up films.

  As an example of the resin composition, Patent Document 1 below includes (A) a polyfunctional epoxy resin (excluding a phenoxy resin), (B) a phenol-based curing agent and / or an active ester-based curing agent, (C A resin composition containing a) a thermoplastic resin, (D) an inorganic filler, and (E) a quaternary phosphonium curing accelerator is disclosed. (C) As a thermoplastic resin, the thermoplastic resin selected from a phenoxy resin, a polyvinyl acetal resin, a polyimide, a polyamide-imide resin, a polyether sulfone resin, and a polysulfone resin is mentioned. (E) As a quaternary phosphonium-based curing accelerator, at least one 4 selected from tetrabutylphosphonium decanoate, (4-methylphenyl) triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate. A grade phosphonium-type hardening accelerator is mentioned.

JP2015-145498A

  When an insulating layer is formed using a conventional resin composition as described in Patent Document 1, the adhesion between the insulating layer and the wiring (metal layer) may not be sufficiently high. For this reason, a metal layer may peel from an insulating layer. In addition, the surface roughness of the surface of the insulating layer may increase.

  The objective of this invention is providing the hardening body which can improve the adhesiveness of an insulating layer and a metal layer, and can make the surface roughness of the surface of an insulating layer small. Moreover, this invention is providing the multilayer substrate using the said hardening body.

  According to a wide aspect of the present invention, there is provided a cured product of a resin composition containing an epoxy compound, a curing agent, an inorganic filler, and polyimide, and the content of the inorganic filler is 30% in 100% by weight of the cured product. % Or more and 90% by weight or less, the cured body has a sea-island structure having a sea part and an island part, an average major axis of the island part is 5 μm or less, and the island part contains the polyimide. The body is provided.

  On the specific situation with the hardening body which concerns on this invention, content of the said polyimide is 3 to 50 weight% in 100 weight% of components except the said inorganic filler in the said hardening body.

  On the specific situation with the hardening body which concerns on this invention, the said hardening | curing agent contains an active ester compound.

  On the specific situation with the hardening body which concerns on this invention, the said resin composition contains a hardening accelerator.

  On the specific situation with the hardening body which concerns on this invention, the said inorganic filler contains a silica.

  On the specific situation with the hardening body which concerns on this invention, content of the said silica is 40 weight% or more in 100 weight% of said hardening bodies.

  In a specific aspect of the cured body according to the present invention, the polyimide has an aliphatic structure having 6 or more carbon atoms.

  On the specific situation with the hardening body which concerns on this invention, the said polyimide is a polyimide except the polyimide which has a siloxane skeleton.

  In a specific aspect of the cured product according to the present invention, the total content of the unreacted product of the epoxy compound and the reacted product of the epoxy compound in 100% by weight of the component excluding the inorganic filler in the cured product. More than the content of the polyimide in 100% by weight of the component excluding the inorganic filler in the cured body.

  According to a wide aspect of the present invention, there is provided a multilayer board comprising a circuit board and an insulating layer disposed on the circuit board, wherein the material of the insulating layer is the above-described cured body.

  The cured body according to the present invention is a cured body of a resin composition containing an epoxy compound, a curing agent, an inorganic filler, and polyimide. In the cured body according to the present invention, the content of the inorganic filler is 30% by weight or more and 90% by weight or less in 100% by weight of the cured body. The cured body according to the present invention has a sea-island structure having a sea part and an island part. In the cured body according to the present invention, the average major axis of the island part is 5 μm or less, and the island part contains the polyimide. Since the cured body according to the present invention has the above-described configuration, the adhesion between the insulating layer and the metal layer can be improved, and the surface roughness of the surface of the insulating layer can be reduced.

FIG. 1 is a cross-sectional view schematically showing a multilayer substrate using a cured body according to an embodiment of the present invention.

  Hereinafter, the present invention will be described in detail.

  The cured body according to the present invention is a cured body of a resin composition containing an epoxy compound, a curing agent, an inorganic filler, and polyimide. The cured body according to the present invention is obtained by allowing the resin composition to cure. The cured body may be a cured body that has been completely cured, or may be a cured body (such as a semi-cured body) that can further progress the curing.

  In 100% by weight of the cured product according to the present invention, the content of the inorganic filler is 30% by weight or more and 90% by weight or less.

  The cured body according to the present invention has a sea-island structure having a sea part and an island part. In the hardened | cured material which concerns on this invention, the average major axis of the said island part is 5 micrometers or less. In the cured body according to the present invention, the island portion contains polyimide.

  In this invention, since said structure is provided, the adhesiveness of the metal layer formed on the surface of a hardening body can be improved. For example, the peel strength of the metal layer with respect to the insulating layer can be increased. In particular, the cured body according to the present invention has a sea-island structure having a sea part and an island part, and the average major axis of the island part being 5 μm or less greatly contributes to the improvement of adhesion. Furthermore, in this invention, since the said island part contains a polyimide, the surface roughness of the surface of an insulating layer can be made small. The average major axis of the island part being 5 μm or less and the fact that the island part contains polyimide greatly contribute to reducing the surface roughness of the surface of the insulating layer.

  Furthermore, in the present invention, since the above-described configuration is provided, since the content of the inorganic filler is particularly 30% by weight or more, the linear expansion coefficient of the insulating layer can be lowered, and the thermal dimensional stability is improved. Can be high.

  Furthermore, in the present invention, since the above-described configuration is provided, it is possible to enhance desmearability. In particular, the cured body according to the present invention has a sea-island structure having a sea part and an island part, and the average major axis of the island part being 5 μm or less greatly contributes to the improvement of desmearability.

  From the viewpoint of effectively increasing the adhesion between the insulating layer and the metal layer, effectively reducing the surface roughness of the surface of the insulating layer, and further improving the desmear property, the average major axis of the island portion is Preferably it is 3 micrometers or less, More preferably, it is 1.5 micrometers or less. The lower limit of the average major axis of the island is not particularly limited. The average major axis of the island part may be 0.1 μm or more.

  Examples of a method for obtaining a cured body having the specific sea-island structure include a method for selecting the type of polyimide, a method for selecting the molecular weight of the polyimide, and a method for selecting the curing conditions.

  The said hardening body contains the component derived from the said epoxy compound and the said hardening | curing agent, contains the said polyimide, and contains the said inorganic filler. The island part includes the polyimide. In this case, the surface roughness of the surface of the insulating layer can be further reduced, and the desmear property can be further improved. The sea part preferably includes a component derived from the epoxy compound and the curing agent, and the sea part preferably includes an inorganic filler. Moreover, when using a hardening accelerator, it is preferable that the said sea part contains the component originating in a hardening accelerator. The content of the inorganic filler contained in 100% by weight of the sea part is preferably larger than the content of the inorganic filler present in 100% by weight of the island part. In this case, small surface roughness and high adhesion can be effectively achieved. Furthermore, the thermal expansion coefficient can be effectively reduced by uneven distribution of the inorganic filler, and the dimensional change due to heat of the insulating layer can be effectively reduced. A particularly excellent effect is obtained when the content of the inorganic filler is 30% by weight or more.

  The cured body according to the present invention is preferably an interlayer insulating material used for a multilayer substrate (preferably a multilayer printed wiring board). The cured body according to the present invention is suitably used for forming an insulating layer in a multilayer substrate (preferably a multilayer printed wiring board). The insulating layer insulates the layers.

  In this invention, it is preferable that the said hardening | curing agent contains an active ester compound. In this case, low dielectric loss tangent, small surface roughness, low coefficient of linear expansion, and high adhesion can be achieved at a higher level. Moreover, since the said hardening | curing agent contains an active ester compound, the component originating in the said epoxy compound and the said hardening | curing agent, and the said polyimide can be phase-separated still more favorably, and said specific sea island structure is made. The hardened body which has can be obtained still more easily.

  When the cured product is heated at 190 ° C. for 90 minutes to obtain a cured product (insulating layer), the average linear expansion coefficient of the cured product at 25 ° C. or more and 150 ° C. or less is preferably 30 ppm / ° C. or less. Preferably it is 25 ppm / ° C. or less. When the average linear expansion coefficient is not more than the above upper limit, the thermal dimensional stability is further improved. The dielectric loss tangent of the cured product at a frequency of 1.0 GHz is preferably 0.005 or less, more preferably 0.004 or less. When the dielectric loss tangent is less than or equal to the upper limit, transmission loss is further suppressed.

  Hereinafter, the details of each component used in the cured product according to the present invention and the resin composition for obtaining the cured product, and the use of the cured product according to the present invention will be described.

[Epoxy compound]
The epoxy compound contained in the resin composition is not particularly limited. A conventionally well-known epoxy compound can be used as this epoxy compound. The epoxy compound refers to an organic compound having at least one epoxy group. As for the said epoxy compound, only 1 type may be used and 2 or more types may be used together.

  Examples of the epoxy compound include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, biphenyl type epoxy resin, biphenyl novolac type epoxy resin, biphenol type epoxy resin, and naphthalene type epoxy resin. Fluorene type epoxy resin, phenol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, anthracene type epoxy resin, epoxy resin having adamantane skeleton, epoxy resin having tricyclodecane skeleton, and triazine nucleus Examples thereof include an epoxy resin having a skeleton.

  The epoxy compound preferably has a biphenyl skeleton, and is preferably a biphenyl type epoxy resin. When the epoxy resin has a biphenyl skeleton, the adhesive strength between the insulating layer and the metal layer is further increased.

  The molecular weight of the epoxy compound is more preferably 1000 or less. In this case, even if the content of the inorganic filler is 30% by weight or more, and even if the content of the inorganic filler is 60% by weight or more, a resin composition having high fluidity can be obtained. For this reason, when the uncured product or B-stage product of the resin composition is laminated on the substrate, the inorganic filler can be uniformly present.

  The molecular weight of the epoxy compound and the molecular weight of the curing agent described later mean the molecular weight that can be calculated from the structural formula when the epoxy compound or the curing agent is not a polymer and when the structural formula of the epoxy compound or the curing agent can be specified. To do. Moreover, when an epoxy compound or a hardening | curing agent is a polymer, a weight average molecular weight is meant.

  The weight average molecular weight indicates a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[Curing agent]
The curing agent contained in the resin composition is not particularly limited. A conventionally known curing agent can be used as the curing agent. As for the said hardening | curing agent, only 1 type may be used and 2 or more types may be used together.

  As the curing agent, cyanate ester compound (cyanate ester curing agent), phenol compound (phenol curing agent), amine compound (amine curing agent), thiol compound (thiol curing agent), imidazole compound, phosphine compound, acid anhydride, Examples include active ester compounds and dicyandiamide. The curing agent preferably has a functional group capable of reacting with the epoxy group of the epoxy compound.

  Examples of the cyanate ester compound include novolac-type cyanate ester resins, bisphenol-type cyanate ester resins, and prepolymers in which these are partially trimerized. As said novolak-type cyanate ester resin, a phenol novolak-type cyanate ester resin, an alkylphenol-type cyanate ester resin, etc. are mentioned. Examples of the bisphenol type cyanate ester resin include bisphenol A type cyanate ester resin, bisphenol E type cyanate ester resin, and tetramethylbisphenol F type cyanate ester resin.

  Commercially available products of the above-mentioned cyanate ester compounds include phenol novolac type cyanate ester resins (Lonza Japan "PT-30" and "PT-60"), and prepolymers (Lonza Japan) in which bisphenol type cyanate ester resins are trimerized. "BA-230S", "BA-3000S", "BTP-1000S", and "BTP-6020S") manufactured by the company.

  Examples of the phenol compound include novolak type phenol, biphenol type phenol, naphthalene type phenol, dicyclopentadiene type phenol, aralkyl type phenol, dicyclopentadiene type phenol and the like.

  Examples of commercially available phenol compounds include novolak-type phenols (“TD-2091” manufactured by DIC, “H-4” manufactured by Meiwa Kasei Co., Ltd.), biphenyl novolac-type phenols (“MEH-7851” manufactured by Meiwa Kasei), and aralkyl. Type phenolic compounds (“MEH-7800” manufactured by Meiwa Kasei Co., Ltd.), phenols having an aminotriazine skeleton (“LA1356” and “LA3018-50P” manufactured by DIC), and the like.

  From the viewpoint of effectively reducing the dielectric loss tangent, effectively reducing the surface roughness, and effectively increasing the adhesion, the curing agent preferably contains an active ester compound. By using an active ester compound, the component derived from the epoxy compound and the curing agent and the polyimide can be phase-separated more favorably, and the cured body having the specific sea-island structure can be further enhanced. It can be easily obtained, the surface roughness after desmearing can be further reduced, and the adhesion can be further enhanced.

  The active ester compound means a compound containing at least one ester bond in the structure and having an aromatic ring bonded to both sides of the ester bond. The active ester compound is obtained, for example, by a condensation reaction between a carboxylic acid compound or thiocarboxylic acid compound and a hydroxy compound or thiol compound. Examples of the active ester compound include a compound represented by the following formula (1).

  In said formula (1), X1 and X2 represent group containing an aromatic ring respectively. Preferable examples of the group containing an aromatic ring include a benzene ring which may have a substituent and a naphthalene ring which may have a substituent. A hydrocarbon group is mentioned as said substituent. The carbon number of the hydrocarbon group is preferably 12 or less, more preferably 6 or less, and still more preferably 4 or less.

  Examples of the combination of X1 and X2 include the following combinations. A combination of a benzene ring which may have a substituent and a benzene ring which may have a substituent. A combination of a benzene ring which may have a substituent and a naphthalene ring which may have a substituent. A combination of a naphthalene ring which may have a substituent and a naphthalene ring which may have a substituent.

  The active ester compound is not particularly limited. As a commercial item of the said active ester compound, "HPC-8000-65T", "EXB9416-70BK", "EXB8100L-65T" by DIC, etc. are mentioned.

  In 100% by weight of the component excluding the inorganic filler and solvent in the resin composition, the total content of the epoxy compound and the curing agent is preferably 65% by weight or more, more preferably 70% by weight or more. Yes, preferably 99% by weight or less, more preferably 97% by weight or less. “100% by weight of the component excluding the inorganic filler and solvent in the resin composition” means that when the resin composition contains the inorganic filler and solvent, “the inorganic filler and solvent in the resin composition”. In the case where the resin composition does not contain the above inorganic filler and contains a solvent, it means “100% by weight of the ingredient excluding the solvent in the resin composition”. “100% by weight of the component excluding the inorganic filler and solvent in the resin composition” means that when the resin composition contains the inorganic filler and does not contain a solvent, “the inorganic filler in the resin composition”. "100% by weight of components excluding material" means "100% by weight of resin composition" when the resin composition does not contain the inorganic filler and solvent. When the total content of the epoxy compound and the curing agent is not less than the above lower limit and not more than the above upper limit, a better cured body can be obtained, and the dimensional change due to heat of the insulating layer can be further suppressed. The content ratio between the epoxy compound and the curing agent is appropriately selected so that the epoxy compound is cured.

[Polyimide]
The polyimide contained in the resin composition is not particularly limited. A conventionally known polyimide can be used as the polyimide. As for the said polyimide, only 1 type may be used and 2 or more types may be used together.

  As the polyimide, a polyimide having an aliphatic structure is preferable. By using a polyimide having an aliphatic structure, when an epoxy compound is used as a curable component, a sea-island structure can be easily formed, and the adhesion between the insulating layer and the metal layer is effectively enhanced, and The surface roughness of the surface of the insulating layer can be effectively reduced. Furthermore, the dielectric loss tangent of a hardening body can be made low by using the polyimide which has an aliphatic structure.

  The polyimide can be obtained by a method of reacting a tetracarboxylic acid anhydride component and an isocyanate component and a method of reacting a tetracarboxylic acid anhydride component and a diamine component. From the viewpoint of excellent solubility, a method of reacting a tetracarboxylic anhydride component and a diamine component is more preferable. Moreover, it is preferable that a diamine component has an aliphatic structure from a viewpoint which is excellent in the availability of a raw material.

  Examples of the tetracarboxylic acid anhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, and 3,3 ′, 4,4′-biphenylsulfone tetracarboxylic acid. Acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyl ether tetra Carboxylic dianhydride, 3,3 ′, 4,4′-dimethyldiphenylsilane tetracarboxylic dianhydride, 3,3 ′, 4,4′-tetraphenylsilane tetracarboxylic dianhydride, 1,2, 3,4-furantetracarboxylic dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) ) Diphenylsulfone dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidenediphthalic dianhydride, 3 , 3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, m-phenylene-bis ( Examples thereof include triphenylphthalic acid dianhydride, bis (triphenylphthalic acid) -4,4′-diphenyl ether dianhydride, and bis (triphenylphthalic acid) -4,4′-diphenylmethane dianhydride.

As the diamine component, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, bis (aminomethyl) norbornane, 3 (4), 8 (9) -bis (aminomethyl) Tricyclo [5.2.1.0 ^2,6 ] decane, 1,1-bis (4-aminophenyl) cyclohexane, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 2,7-diaminofluorene, 4 , 4′-ethylenedianiline, isophoronediamine, 4,4′-methylenebis (cyclohexylamine), 4,4′-methylenebis (2,6-diethylaniline), 4,4′-methylenebis (2-ethyl-6- Methylaniline), 4,4′-methylenebis (2-methylcyclohexylamine), 1,4-diaminobutane, 1,10- Diaminodecane, 1,12-diaminododecane, 1,7-diaminoheptane, 1,6-diaminohexane, 1,5-diaminopentane, 1,8-diaminooctane, 1,3-diaminopropane, 1,11-diamino Examples include undecane, 2-methyl-1,5-diaminopentane, and dimer acid diamine. The diamine component preferably has a ring structure, and more preferably has an alicyclic structure, because the effect of the present invention is further improved.

  When the polyimide has an aliphatic structure, the carbon number of the aliphatic structure is preferably 6 or more, more preferably 8 or more, preferably 50 or less, more preferably 40 or less. When the number of carbons is not less than the above lower limit, a finer sea-island structure can be easily formed, so that desmearing properties are effectively increased, and the surface roughness of the surface of the insulating layer after desmearing can be kept small. However, the adhesion between the insulating layer and the metal layer is effectively increased, and the dielectric loss tangent is further decreased. When the carbon number is not more than the above upper limit, the storage stability of the resin composition (interlayer insulating material) is further increased, and a sea-island structure can be formed without lowering the heat resistance of the insulating layer. Further, if the carbon number is not more than the above upper limit, it is easy to make the average major axis of the island part 5 μm or less, so that the surface roughness of the surface of the insulating layer after desmearing is further reduced, and the insulating layer and the metal The adhesive strength with the layer is further increased, the coefficient of thermal expansion of the insulating layer is further decreased, and the insulating property is further decreased.

  By changing the molecular weight of the polyimide, it is possible to arbitrarily control the ease of forming the sea-island structure and the size of the island. From the viewpoint of further enhancing the storage stability of the resin composition (interlayer insulating material) and further enhancing the embedding property of the B stage film in the holes or irregularities of the circuit board, the weight average molecular weight of the polyimide is preferably 5000. As mentioned above, More preferably, it is 10,000 or more, Preferably it is 100,000 or less, More preferably, it is 50000 or less. When the weight average molecular weight of the polyimide is not less than the above lower limit and not more than the above upper limit, it becomes easy to form a sea-island structure, and as a result, the thermal expansion coefficient becomes lower and the adhesive strength between the insulating layer and the metal layer becomes higher Increases smear removal.

  The weight average molecular weight of the polyimide indicates a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

  The structure of the end of the polyimide is not particularly limited, but the polyimide preferably has a functional group capable of reacting with an epoxy group. When polyimide has such a functional group, the heat resistance of the insulating layer can be further improved. The functional group is preferably an amino group or an acid anhydride group, and particularly preferably an acid anhydride group. When the functional group is an acid anhydride group, an increase in melt viscosity can be effectively suppressed even when polyimide is used. When the amount of acid anhydride is increased during the synthesis of polyimide, the terminal can be converted into an acid anhydride group, and when the amount of amine is increased, the terminal can be converted into an amino group.

  From the viewpoint of effectively increasing the adhesion between the insulating layer and the metal layer and further enhancing the desmear property, the polyimide preferably does not have a siloxane skeleton. The polyimide is preferably a polyimide excluding a polyimide having a siloxane skeleton.

  In 100% by weight of the component excluding the inorganic filler and solvent in the resin composition (interlayer insulating material), the content of the polyimide is preferably 3% by weight or more, more preferably 5% by weight or more, and still more preferably 10%. % By weight or more, preferably 50% by weight or less, more preferably 45% by weight, still more preferably 35% by weight or less, and particularly preferably 25% by weight or less. When the content of the polyimide is not less than the above lower limit, desmearing properties are effectively increased, and the surface roughness of the surface of the insulating layer after desmearing is kept small, while the adhesion between the insulating layer and the metal layer is reduced. Effectively increases, and the dielectric loss tangent is further decreased. When the content of the polyimide is not more than the above upper limit, the storage stability of the resin composition (interlayer insulating material) is further enhanced. Moreover, since it is easy to make the average major axis of the island part 5 μm or less, the surface roughness of the surface of the insulating layer after desmearing is further reduced, and the adhesive strength between the insulating layer and the metal layer is further increased. In addition, the thermal expansion coefficient of the insulating layer is further lowered, and the insulating property is further lowered.

  In 100% by weight of the component excluding the inorganic filler in the cured body, the content of the polyimide is preferably 3% by weight or more, more preferably 5% by weight or more, further preferably 10% by weight or more, preferably It is 50% by weight or less, more preferably 45% by weight, still more preferably 35% by weight or less, and particularly preferably 25% by weight or less. “100% by weight of the component excluding the inorganic filler in the cured product” means “100% by weight of the component excluding the inorganic filler in the cured product” when the cured product contains the inorganic filler. And when a hardening | curing agent does not contain the said inorganic filler, it means "100 weight% of hardening bodies." When the content of the polyimide is not less than the above lower limit, desmearing properties are effectively increased, and the surface roughness of the surface of the insulating layer after desmearing is kept small, while the adhesion between the insulating layer and the metal layer is reduced. Effectively increases, and the dielectric loss tangent is further decreased. When the content of the polyimide is not more than the above upper limit, the storage stability of the resin composition (interlayer insulating material) is further enhanced. Moreover, since it is easy to make the average major axis of the island part 5 μm or less, the surface roughness of the surface of the insulating layer after desmearing is further reduced, and the adhesive strength between the insulating layer and the metal layer is further increased. In addition, the thermal expansion coefficient of the insulating layer is further lowered, and the insulating property is further lowered.

  The content A1 of the epoxy compound in 100% by weight of the component excluding the inorganic filler and the solvent in the resin composition is the same as that in 100% by weight of the component excluding the inorganic filler and the solvent in the resin composition. The content is preferably larger than the polyimide content B1. When the resin composition satisfies the above preferred embodiment, a cured body having a sea-island structure containing the polyimide in the island portion can be obtained more easily, and the surface roughness of the insulating layer after desmearing can be further reduced. The adhesion between the insulating layer and the metal layer can be further enhanced. Since these effects are more effectively exhibited, the content A1 is preferably 0.1% by weight or more, more preferably 1% by weight or more, and more preferably 3% by weight than the content B1. More is more preferable.

  The total content A2 of the unreacted product of the epoxy compound and the reacted product of the epoxy compound in 100% by weight of the component excluding the inorganic filler in the cured product excludes the inorganic filler in the cured product. The content is preferably larger than the content B2 of the polyimide in 100% by weight of the component. When the cured body satisfies the above preferred embodiment, a cured body having a sea-island structure containing the polyimide in the island portion can be obtained further, and the surface roughness of the insulating layer after desmearing can be further reduced. And the adhesion between the insulating layer and the metal layer can be further enhanced. Since these effects are more effectively exhibited, the content A2 is preferably more than 0.1% by weight, more preferably more than 1% by weight, more preferably 3% by weight, more than the content B2. More is more preferable.

[Thermoplastic resin other than polyimide]
The resin composition may contain a thermoplastic resin other than polyimide.

  Examples of the thermoplastic resin include polyvinyl acetal resin and phenoxy resin. As for the said thermoplastic resin, only 1 type may be used and 2 or more types may be used together.

  Regardless of the curing environment, the thermoplastic resin is preferably a phenoxy resin from the viewpoint of effectively reducing the dielectric loss tangent and effectively improving the adhesion of the metal wiring. By using the phenoxy resin, deterioration of the embedding property of the resin film with respect to the holes or irregularities of the circuit board and non-uniformity of the inorganic filler are suppressed. Moreover, since the melt viscosity can be adjusted by using a phenoxy resin, the dispersibility of the inorganic filler is improved, and the resin composition or the B-stage film is difficult to wet and spread in an unintended region during the curing process. The phenoxy resin contained in the resin composition is not particularly limited. A conventionally known phenoxy resin can be used as the phenoxy resin. As for the said phenoxy resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the phenoxy resin include phenoxy resins having a skeleton such as a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a biphenyl skeleton, a novolac skeleton, a naphthalene skeleton, and an imide skeleton.

  Examples of commercially available phenoxy resins include “YP50”, “YP55” and “YP70” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., and “1256B40”, “4250”, “4256H40” manufactured by Mitsubishi Chemical Corporation, “ 4275 "," YX6954BH30 "," YX8100BH30 ", and the like.

  From the viewpoint of obtaining a more excellent resin film due to storage stability, the weight average molecular weight of the thermoplastic resin is preferably 5000 or more, more preferably 10,000 or more, preferably 100,000 or less, more preferably 50000 or less. .

  The said weight average molecular weight of the said thermoplastic resin shows the weight average molecular weight in polystyrene conversion measured by gel permeation chromatography (GPC).

  The content of the thermoplastic resin is not particularly limited. In 100% by weight of the component excluding the inorganic filler and solvent in the resin composition and in 100% by weight of the component excluding the inorganic filler in the cured body, the content of the thermoplastic resin (the thermoplastic resin is phenoxy) In the case of a resin, the content of the phenoxy resin is preferably 2% by weight or more, more preferably 4% by weight or more. In 100% by weight of the component excluding the inorganic filler and solvent in the resin composition and in 100% by weight of the component excluding the inorganic filler in the cured body, the content of the thermoplastic resin (the thermoplastic resin is phenoxy) In the case of a resin, the content of the phenoxy resin) is preferably 15% by weight or less, more preferably 10% by weight or less. When the content of the thermoplastic resin is not less than the above lower limit and not more than the above upper limit, the embedding property of the resin composition or the B stage film with respect to the holes or irregularities of the circuit board becomes good. When the content of the thermoplastic resin is equal to or more than the lower limit, the resin composition can be more easily formed into a film, and a better insulating layer can be obtained. When the content of the thermoplastic resin is not more than the above upper limit, the thermal expansion coefficient of the insulating layer is further lowered. The surface roughness of the surface of the insulating layer is further reduced, and the adhesive strength between the insulating layer and the metal layer is further increased.

[Inorganic filler]
The resin composition includes an inorganic filler. By using the inorganic filler, the dimensional change due to heat of the insulating layer is further reduced. Further, the dielectric loss tangent of the cured body is further reduced.

  Examples of the inorganic filler include silica, talc, clay, mica, hydrotalcite, alumina, magnesium oxide, aluminum hydroxide, aluminum nitride, and boron nitride.

  The surface roughness of the insulating layer is reduced, the adhesive strength between the insulating layer and the metal layer is further increased, finer wiring is formed on the surface of the cured body, and better insulation reliability is achieved by the cured body. From the viewpoint of imparting the above, the inorganic filler is preferably silica or alumina, more preferably silica, and still more preferably fused silica. The inorganic filler preferably contains silica. By using silica, the thermal expansion coefficient of the insulating layer is further reduced, the surface roughness of the surface of the insulating layer is effectively reduced, and the adhesive strength between the insulating layer and the metal layer is effectively increased. The shape of silica is preferably spherical.

  The average particle diameter of the inorganic filler is preferably 10 nm or more, more preferably 50 nm or more, further preferably 150 nm or more, preferably 20 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less, and particularly preferably 1 μm. It is as follows. When the average particle size of the inorganic filler is not less than the above lower limit and not more than the above upper limit, the size of the holes formed by the roughening treatment or the like becomes fine, and the number of holes increases. As a result, the adhesive strength between the insulating layer and the metal layer is further increased.

  A median diameter (d50) value of 50% is employed as the average particle diameter of the inorganic filler. The average particle size can be measured using a laser diffraction / scattering particle size distribution measuring apparatus.

  Each of the inorganic fillers is preferably spherical, and more preferably spherical silica. In this case, the surface roughness of the surface of the insulating layer is effectively reduced, and the adhesive strength between the insulating layer and the metal layer is effectively increased. When each of the inorganic fillers is spherical, the aspect ratio of each of the inorganic fillers is preferably 2 or less, more preferably 1.5 or less.

  In 100% by weight of the component excluding the solvent in the resin composition and in 100% by weight of the cured product, the content of the inorganic filler is 30% by weight or more, preferably 40% by weight or more, more preferably 50% by weight. More preferably, it is 60% by weight or more. In 100% by weight of the component excluding the solvent in the resin composition and in 100% by weight of the cured product, the content of the inorganic filler is 90% by weight or less, preferably 85% by weight or less, more preferably 80% by weight. Hereinafter, it is more preferably 75% by weight or less. “100% by weight of the component excluding the solvent in the resin composition” means “100% by weight of the component excluding the solvent in the resin composition” when the resin composition contains a solvent. When no solvent is contained, it means “100% by weight of resin composition”. When content of the said inorganic filler is more than the said minimum, the said inorganic filler becomes easy to be unevenly distributed in the sea-island structure part which does not contain a polyimide by the phase separation after hardening by a polyimide. For this reason, when the said inorganic filler is a silica, a thermal expansion coefficient can be effectively made small by the combination of a polyimide and a silica, and the dimensional change by the heat | fever of an insulating layer can be made small effectively. . A particularly high effect is obtained when 30% by weight or more of the inorganic filler and the active ester compound are combined.

  In 100% by weight of the component excluding the solvent in the resin composition and in 100% by weight of the cured product, the content of the silica is preferably 30% by weight or more, more preferably 40% by weight or more, and further preferably 50% by weight or more. Particularly preferably, it is 60% by weight or more. In 100% by weight of the component excluding the solvent in the resin composition and in 100% by weight of the cured product, the content of the silica is preferably 90% by weight or less, more preferably 85% by weight or less, still more preferably 80% by weight or less. Particularly preferably, it is 75% by weight or less. When the content of the silica is equal to or more than the lower limit, the silica is likely to be unevenly distributed in a sea-island structure portion that does not contain polyimide due to phase separation after curing with polyimide. For this reason, the thermal expansion coefficient can be effectively reduced by the combination of polyimide and silica, and the dimensional change due to heat of the insulating layer can be effectively reduced. A particularly high effect is obtained when 30% by weight or more of silica and an active ester compound are combined.

  The inorganic filler is preferably surface-treated, more preferably a surface-treated product with a coupling agent, and still more preferably a surface-treated product with a silane coupling agent. As a result, the surface roughness of the surface of the insulating layer is further reduced, the adhesive strength between the insulating layer and the metal layer is further increased, finer wiring is formed on the surface of the cured body, and even better. Insulation reliability between wirings and interlayer insulation reliability can be imparted to the cured body.

  Examples of the coupling agent include silane coupling agents, titanium coupling agents, and aluminum coupling agents. Examples of the silane coupling agent include methacryl silane, acrylic silane, amino silane, imidazole silane, vinyl silane, and epoxy silane. From the viewpoint of allowing the inorganic filler to be unevenly distributed in the sea-island structure portion that does not contain polyimide, aminosilane, imidazolesilane, and epoxysilane are preferable as the silane coupling agent.

[Curing accelerator]
The resin composition preferably contains a curing accelerator. By using the curing accelerator, the curing rate is further increased. By rapidly curing the resin film, the number of unreacted functional groups is reduced, and as a result, the crosslinking density is increased. The said hardening accelerator is not specifically limited, A conventionally well-known hardening accelerator can be used. As for the said hardening accelerator, only 1 type may be used and 2 or more types may be used together.

  Examples of the curing accelerator include imidazole compounds, phosphorus compounds, amine compounds, and organometallic compounds.

  Examples of the imidazole compound include 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl- 2-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-un Decylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2 ′ -Methyl Midazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-undecylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6 [2′-Ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine Isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-dihydroxymethylimidazole Can be mentioned.

  Examples of the phosphorus compound include triphenylphosphine.

  Examples of the amine compound include diethylamine, triethylamine, diethylenetetramine, triethylenetetramine and 4,4-dimethylaminopyridine.

  Examples of the organometallic compound include zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonate cobalt (II), and trisacetylacetonate cobalt (III).

  The content of the curing accelerator is not particularly limited. In 100% by weight of the component excluding the inorganic filler and solvent in the resin composition and in 100% by weight of the component excluding the inorganic filler in the cured body, the content of the curing accelerator is preferably 0.01. % By weight or more, more preferably 0.9% by weight or more, preferably 5.0% by weight or less, more preferably 3.0% by weight or less. When the content of the curing accelerator is not less than the above lower limit and not more than the above upper limit, the resin film is efficiently cured. If content of the said hardening accelerator is a more preferable range, the storage stability of a resin composition will become still higher and a much more preferable hardening body will be obtained.

[solvent]
The resin composition does not contain or contains a solvent. By using the solvent, the viscosity of the resin composition can be controlled within a suitable range, and the coatability of the resin composition can be improved. Moreover, the said solvent may be used in order to obtain the slurry containing the said inorganic filler. As for the said solvent, only 1 type may be used and 2 or more types may be used together.

  Examples of the solvent include acetone, methanol, ethanol, butanol, 2-propanol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 2-acetoxy-1-methoxypropane, toluene, xylene, methyl ethyl ketone, Examples thereof include N, N-dimethylformamide, methyl isobutyl ketone, N-methyl-pyrrolidone, n-hexane, cyclohexane, cyclohexanone, and naphtha as a mixture.

  Most of the solvent is preferably removed when the resin composition is formed into a film. Therefore, the boiling point of the solvent is preferably 200 ° C. or lower, more preferably 180 ° C. or lower. The content of the solvent in the resin composition is not particularly limited. The content of the solvent can be appropriately changed in consideration of the coating property of the resin composition.

[Other ingredients]
For the purpose of improving impact resistance, heat resistance, resin compatibility, workability, etc., the resin composition includes a leveling agent, a flame retardant, a coupling agent, a colorant, an antioxidant, an ultraviolet degradation inhibitor, You may add other thermosetting resins other than an antifoamer, a thickener, a thixotropic agent, and an epoxy compound.

  Examples of the coupling agent include silane coupling agents, titanium coupling agents, and aluminum coupling agents. Examples of the silane coupling agent include vinyl silane, amino silane, imidazole silane, and epoxy silane.

  Examples of the other thermosetting resins include polyphenylene ether resins, divinyl benzyl ether resins, polyarylate resins, diallyl phthalate resins, polyimide resins, benzoxazine resins, benzoxazole resins, bismaleimide resins, and acrylate resins.

(Resin film (B stage film) and laminated film)
A resin film (B stage film) can be obtained by molding the resin composition described above into a film. The resin film is preferably a B stage film.

  From the viewpoint of more uniformly controlling the degree of cure of the resin film, the thickness of the resin film is preferably 5 μm or more, and preferably 200 μm or less.

  As a method for forming the resin composition into a film, for example, an extrusion molding method is used in which the resin composition is melt-kneaded using an extruder, extruded, and then formed into a film using a T-die or a circular die. And a casting molding method in which a resin composition containing a solvent is cast to form a film, and other conventionally known film molding methods. The extrusion molding method or the casting molding method is preferable because it can cope with the reduction in thickness. The film includes a sheet.

  The resin composition is formed into a film and obtained by heating and drying at 50 ° C. to 150 ° C. for 1 minute to 10 minutes, for example, to such an extent that curing by heat does not proceed excessively, thereby obtaining a resin film that is a B stage film. Can do.

  The film-like resin composition that can be obtained by the drying process as described above is referred to as a B-stage film. The B-stage film is a film-shaped resin composition in a semi-cured state. The semi-cured body is not completely cured and curing can proceed further.

  The resin film may not be a prepreg. When the resin film is not a prepreg, migration does not occur along a glass cloth or the like. Further, when laminating or precuring the resin film, the surface is not uneven due to the glass cloth. The said resin composition can be used suitably in order to form a laminated film provided with metal foil or a base material, and the resin film laminated | stacked on the surface of this metal foil or base material. The resin film in the laminated film is formed from the resin composition. The metal foil is preferably a copper foil.

  Examples of the substrate of the laminated film include polyester resin films such as polyethylene terephthalate film and polybutylene terephthalate film, olefin resin films such as polyethylene film and polypropylene film, and polyimide resin film. The surface of the base material may be subjected to a release treatment as necessary.

  When the resin composition and the resin film are used as an insulating layer of a circuit, the thickness of the insulating layer formed of the resin composition or the resin film is equal to or greater than the thickness of the conductor layer (metal layer) forming the circuit. It is preferable that The thickness of the insulating layer is preferably 5 μm or more, and preferably 200 μm or less.

(Printed wiring board)
The resin composition and the resin film are suitably used for forming an insulating layer in a printed wiring board.

  The printed wiring board can be obtained, for example, by heat-pressing the resin film.

  A metal foil can be laminated on one side or both sides of the resin film. The method for laminating the resin film and the metal foil is not particularly limited, and a known method can be used. For example, the resin film can be laminated on the metal foil using an apparatus such as a parallel plate press or a roll laminator while applying pressure while heating or without heating.

(Copper-clad laminate and multilayer board)
The resin composition and the resin film are preferably used for obtaining a copper-clad laminate. An example of the copper-clad laminate is a copper-clad laminate including a copper foil and a resin film laminated on one surface of the copper foil. The resin film of this copper-clad laminate is formed from the resin composition.

  The thickness of the copper foil of the copper-clad laminate is not particularly limited. The thickness of the copper foil is preferably in the range of 1 μm to 50 μm. Moreover, in order to raise the adhesive strength of the insulating layer which hardened the said resin film, and copper foil, it is preferable that the said copper foil has a fine unevenness | corrugation on the surface. The method for forming the unevenness is not particularly limited. Examples of the method for forming the unevenness include a formation method by treatment using a known chemical solution.

  The resin composition and the resin film are preferably used for obtaining a multilayer substrate. As an example of the multilayer substrate, a multilayer substrate including a circuit substrate and an insulating layer stacked on the surface of the circuit substrate can be given. The insulating layer of this multilayer substrate is formed of the resin film using a resin film obtained by forming the resin composition into a film. The material of the insulating layer is the above-described cured body. Moreover, the insulating layer of the multilayer substrate may be formed of the resin film of the laminated film using a laminated film. The insulating layer is preferably laminated on the surface of the circuit board on which the circuit is provided. Part of the insulating layer is preferably embedded between the circuits.

  The multilayer board may be a multilayer printed wiring board. The multilayer printed wiring board includes a circuit board, a plurality of insulating layers arranged on the circuit board, and a metal layer arranged between the plurality of insulating layers. The material of the insulating layer is the above-described cured body. A metal layer may be disposed on the outer surface of the insulating layer farthest from the circuit board among the plurality of insulating layers.

  In the multilayer substrate and the multilayer printed wiring board, it is preferable that the surface of the insulating layer opposite to the surface on which the circuit substrate is laminated is roughened.

  The roughening method can be any conventionally known roughening method and is not particularly limited. The surface of the insulating layer may be subjected to a swelling treatment before the roughening treatment.

  Moreover, it is preferable that the said multilayer substrate is further equipped with the copper plating layer laminated | stacked on the surface by which the roughening process of the said insulating layer was carried out.

  As another example of the multilayer board, the circuit board, the insulating layer laminated on the surface of the circuit board, and the surface of the insulating layer opposite to the surface on which the circuit board is laminated are laminated. And a multilayer substrate provided with copper foil. The insulating layer and the copper foil are formed by curing the resin film using a copper-clad laminate including a copper foil and a resin film laminated on one surface of the copper foil. preferable. Furthermore, it is preferable that the copper foil is etched and is a copper circuit.

  Another example of the multilayer substrate is a multilayer substrate including a circuit board and a plurality of insulating layers stacked on the surface of the circuit board. At least one of the plurality of insulating layers arranged on the circuit board is formed using a resin film obtained by forming the resin composition into a film. It is preferable that the multilayer substrate further includes a circuit laminated on at least one surface of the insulating layer formed using the resin film.

  FIG. 1 is a cross-sectional view schematically showing a multilayer substrate using a cured body according to an embodiment of the present invention.

  A multilayer substrate 11 shown in FIG. 1 is a multilayer printed wiring board. In the multilayer substrate 11, a plurality of insulating layers 13 to 16 are laminated on the upper surface 12 a of the circuit substrate 12. The insulating layers 13 to 16 are cured body layers. A metal layer 17 is formed in a partial region of the upper surface 12 a of the circuit board 12. Among the plurality of insulating layers 13 to 16, the metal layer 17 is formed in a partial region of the upper surface of the insulating layers 13 to 15 other than the insulating layer 16 located on the outer surface opposite to the circuit board 12 side. Has been. The metal layer 17 is a circuit. Metal layers 17 are respectively disposed between the circuit board 12 and the insulating layer 13 and between the stacked insulating layers 13 to 16. The lower metal layer 17 and the upper metal layer 17 are connected to each other by at least one of via hole connection and through hole connection (not shown).

  In the multilayer substrate 11, the insulating layers 13 to 16 are formed of the cured body. In this embodiment, since the surfaces of the insulating layers 13 to 16 are roughened, fine holes (not shown) are formed on the surfaces of the insulating layers 13 to 16. Further, the metal layer 17 reaches the inside of the fine hole. Moreover, in the multilayer substrate 11, the width direction dimension (L) of the metal layer 17 and the width direction dimension (S) of the part in which the metal layer 17 is not formed can be made small. In the multilayer substrate 11, good insulation reliability is imparted between an upper metal layer and a lower metal layer that are not connected by via-hole connection and through-hole connection (not shown).

(Roughening treatment and swelling treatment)
It is preferable that the said resin composition is used in order to obtain the hardening body by which a roughening process or a desmear process is carried out. The cured body includes a precured body that can be further cured.

  In order to form fine irregularities on the surface of the cured body obtained by precuring the resin composition, the cured body is preferably subjected to a roughening treatment. Prior to the roughening treatment, the cured body is preferably subjected to a swelling treatment. The cured body is preferably swelled after preliminary curing and before the roughening treatment, and further cured after the roughening treatment. However, the cured body does not necessarily have to undergo a swelling treatment.

  As a method for the swelling treatment, for example, a method of treating a cured product with an aqueous solution or an organic solvent dispersion of a compound mainly composed of ethylene glycol or the like is used. The swelling liquid used for the swelling treatment generally contains an alkali as a pH adjuster or the like. The swelling liquid preferably contains sodium hydroxide. Specifically, for example, the swelling treatment is performed by treating the cured body with a 40 wt% ethylene glycol aqueous solution at a treatment temperature of 30 ° C. to 85 ° C. for 1 minute to 30 minutes. The swelling treatment temperature is preferably in the range of 50 ° C to 85 ° C. When the temperature of the swelling treatment is too low, it takes a long time for the swelling treatment, and the adhesive strength between the cured body and the metal layer tends to be low.

  For the roughening treatment, for example, a chemical oxidizing agent such as a manganese compound, a chromium compound, or a persulfuric acid compound is used. These chemical oxidizers are used as an aqueous solution or an organic solvent dispersion after water or an organic solvent is added. The roughening liquid used for the roughening treatment generally contains an alkali as a pH adjuster or the like. The roughening solution preferably contains sodium hydroxide.

  Examples of the manganese compound include potassium permanganate and sodium permanganate. Examples of the chromium compound include potassium dichromate and anhydrous potassium chromate. Examples of the persulfate compound include sodium persulfate, potassium persulfate, and ammonium persulfate.

  The method for the roughening treatment is not particularly limited. As a method for the above roughening treatment, for example, using a 30 g / L to 90 g / L permanganate or permanganate solution and a 30 g / L to 90 g / L sodium hydroxide solution at a treatment temperature of 30 ° C. to 85 ° C. A method of treating the cured body under conditions of 1 minute to 30 minutes is preferable. The temperature of the roughening treatment is preferably in the range of 50 ° C to 85 ° C. The number of times of the roughening treatment is preferably once or twice.

  The arithmetic average roughness Ra of the surface of the cured body is preferably 10 nm or more, preferably less than 200 nm, more preferably less than 100 nm, and still more preferably less than 50 nm. When the arithmetic average roughness Ra is not less than the above lower limit and not more than the above upper limit, the conductor loss of the electric signal can be effectively suppressed, and the transmission loss can be largely suppressed. Furthermore, finer wiring can be formed on the surface of the cured body. The arithmetic average roughness Ra is measured according to JIS B0601 (1994).

(Desmear treatment)
A through-hole may be formed in the cured body obtained by pre-curing the resin composition. In the multilayer substrate or the like, a via or a through hole is formed as a through hole. For example, the via can be formed by irradiation with a laser such as a CO ₂ laser. The diameter of the via is not particularly limited, but is about 60 μm to 80 μm. Due to the formation of the through hole, a smear that is a resin residue derived from the resin component contained in the cured body is often formed at the bottom of the via.

  In order to remove the smear, the surface of the cured body is preferably desmeared. The desmear process may also serve as a roughening process.

  In the desmear treatment, for example, a chemical oxidant such as a manganese compound, a chromium compound, or a persulfate compound is used in the same manner as the roughening treatment. These chemical oxidizers are used as an aqueous solution or an organic solvent dispersion after water or an organic solvent is added. The desmear treatment liquid used for the desmear treatment generally contains an alkali. The desmear treatment liquid preferably contains sodium hydroxide.

  The method for the desmear treatment is not particularly limited. Examples of the desmear treatment method include 30 g / L to 90 g / L permanganic acid or permanganate solution and 30 g / L to 90 g / L sodium hydroxide solution. A method of treating the cured body once or twice under conditions of from 30 minutes to 30 minutes is preferable. It is preferable that the temperature of the said desmear process exists in the range of 50 to 85 degreeC.

  By using the resin composition, the surface roughness of the desmeared insulating layer is sufficiently reduced.

  Hereinafter, the present invention will be specifically described by giving examples and comparative examples. The present invention is not limited to the following examples.

(Epoxy compound)
Biphenyl type epoxy resin (“NC-3000” manufactured by Nippon Kayaku Co., Ltd.)
Naphthalene type epoxy resin (“HP-4032D” manufactured by DIC)
Triazine ring epoxy resin (“TEPIC-SP” manufactured by Nissan Chemical Co., Ltd.)
Fluorene type epoxy resin ("PG-100" manufactured by Osaka Gas Chemical Company)
Dicyclopentadiene type epoxy resin (“XD-1000” manufactured by Nippon Kayaku Co., Ltd.)
Naphthalene type epoxy resin (“ESN-475V” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
Bisphenol A type epoxy resin (“YD-8125G” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)

(Curing agent)
Active ester resin-containing liquid (DIC Corporation "EXB-9416-70BK", solid content 70 wt%)
Active ester resin-containing liquid (manufactured by DIC "HPC-8000-65T", solid content 65% by weight)
Cyanate ester resin-containing liquid (Lonza "BA-3000S", solid content 75% by weight)
Carbodiimide resin-containing liquid (Nisshinbo Chemical "V-03", solid content 50 wt%)
Novolac type phenolic resin (“H-4” manufactured by Meiwa Kasei Co., Ltd.)

(Curing accelerator)
Dimethylaminopyridine (“DMAP” manufactured by Wako Pure Chemical Industries, Ltd.)

(Inorganic filler)
Silica-containing slurry (silica 75 wt%: “SC4050-HOA” manufactured by Admatechs, average particle size 1.0 μm, aminosilane treatment, cyclohexanone 25 wt%)

(Acrylic rubber)
Glycidyl acrylate or glycidyl methacrylate-containing acrylic rubber (manufactured by Nagase ChemteX Corporation, “HTR-860P-3”)

(polystyrene)
Polystyrene (Toyo Styrene Co., “HRM12”)

(Polyimide)
(1) Solution of polyimide (1) which is a reaction product of tetracarboxylic anhydride and diamine (non-volatile content: 26.6% by weight): synthesized in Synthesis Example 1 below.

(Synthesis Example 1)
In a reaction vessel equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction tube, 300.0 g of tetracarboxylic dianhydride (“BisDA-1000” manufactured by SABIC Japan LLC) and 665.5 g of cyclohexanone And the solution in the container was heated to 60 ° C. Then, 137.4 g of 4,4′-methylenebis (2-methylcyclohexylamine) (manufactured by Tokyo Chemical Industry Co., Ltd., carbon number 15 of aliphatic structure) was added dropwise. Thereafter, 121.0 g of methylcyclohexane and 423.5 g of ethylene glycol dimethyl ether were added, and an imidization reaction was performed at 140 ° C. for 10 hours to obtain a solution of polyimide (1) (nonvolatile content: 26.6% by weight). . The molecular weight (weight average molecular weight) of the obtained polyimide (1) was 20000. The molar ratio of acid component / amine component was 1.04.

GPC (gel permeation chromatography) measurement:
Using a high-performance liquid chromatograph system manufactured by Shimadzu Corporation, measurement was performed at a column temperature of 40 ° C. and a flow rate of 1.0 ml / min using tetrahydrofuran (THF) as a developing medium. “SPD-10A” was used as a detector, and two columns of “KF-804L” (exclusion limit molecular weight 400,000) manufactured by Shodex were connected in series. “TSK standard polystyrene” manufactured by Tosoh Corporation is used as the standard polystyrene, and the weight average molecular weight Mw = 354,000, 189,000, 98,900, 37,200, 17,100, 9,830, 5,870, 2, Calibration curves were generated using 500, 1,050, 500 substances and molecular weight calculations were performed.

  (2) A solution of polyimide (2) which is a reaction product of tetracarboxylic acid anhydride and diamine (nonvolatile content: 25.6% by weight): synthesized in Synthesis Example 2 below.

(Synthesis Example 2)
In a reaction vessel equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction tube, 300.0 g of tetracarboxylic dianhydride (“BisDA-1000” manufactured by SABIC Japan LLC) and 665.5 g of cyclohexanone And the solution in the container was heated to 60 ° C. Then, 115.5 g of 1,12-diaminododecane (manufactured by Tokyo Chemical Industry Co., Ltd., aliphatic structure carbon number 12) was dropped. Thereafter, 121.0 g of methylcyclohexane and 423.5 g of ethylene glycol dimethyl ether were added, and an imidization reaction was performed at 140 ° C. for 10 hours to obtain a polyimide (2) solution (nonvolatile content: 25.6% by weight). . The molecular weight (weight average molecular weight) of the obtained polyimide (2) was 20000. The molar ratio of acid component / amine component was 1.04.

  (3) A solution of polyimide (3) which is a reaction product of tetracarboxylic anhydride and diamine (nonvolatile content: 25.4% by weight): synthesized in Synthesis Example 3 below.

(Synthesis Example 3)
In a reaction vessel equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction tube, 300.0 g of tetracarboxylic dianhydride (“BisDA-1000” manufactured by SABIC Japan LLC) and 665.5 g of cyclohexanone And the solution in the container was heated to 60 ° C. Then, 115.5 g of 3 (4), 8 (9) -bis (aminomethyl) tricyclo [5.2.1.0 ^2,6 ] decane (manufactured by Tokyo Chemical Industry Co., Ltd., carbon number 12 of aliphatic structure) It was dripped. Thereafter, 121.0 g of methylcyclohexane and 423.5 g of ethylene glycol dimethyl ether were added, and an imidization reaction was performed at 140 ° C. for 10 hours to obtain a polyimide (3) solution (nonvolatile content: 25.4% by weight). . The molecular weight (weight average molecular weight) of the obtained polyimide (3) was 20000. The molar ratio of acid component / amine component was 1.04.

  (4) A solution of polyimide (4) which is a reaction product of tetracarboxylic anhydride and diamine (nonvolatile content: 25.6% by weight): synthesized in Synthesis Example 4 below.

(Synthesis Example 4)
In a reaction vessel equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction tube, 300.0 g of tetracarboxylic dianhydride (“BisDA-1000” manufactured by SABIC Japan LLC) and 665.5 g of cyclohexanone And the solution in the container was heated to 60 ° C. Then, 115.5 g of 1,12-diaminododecane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise. Thereafter, 121.0 g of methylcyclohexane and 423.5 g of ethylene glycol dimethyl ether were added, and an imidization reaction was performed at 140 ° C. for 3 hours to obtain a polyimide (4) solution (nonvolatile content: 25.6% by weight). . The molecular weight (weight average molecular weight) of the obtained polyimide (4) was 4500. The molar ratio of acid component / amine component was 1.04.

  (5) A solution of polyimide (5) which is a reaction product of tetracarboxylic acid anhydride and diamine (nonvolatile content: 25.6% by weight): synthesized in Synthesis Example 5 below.

(Synthesis Example 5)
In a reaction vessel equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction tube, 300.0 g of tetracarboxylic dianhydride (“BisDA-1000” manufactured by SABIC Japan LLC) and 665.5 g of cyclohexanone And the solution in the container was heated to 60 ° C. Then, 115.5 g of 1,12-diaminododecane (manufactured by Tokyo Chemical Industry Co., Ltd., carbon number 4 of aliphatic structure) was added dropwise. Thereafter, 121.0 g of methylcyclohexane and 423.5 g of ethylene glycol dimethyl ether were added, and an imidization reaction was performed at 140 ° C. for 16 hours to obtain a polyimide (5) solution (nonvolatile content: 25.6% by weight). . The molecular weight (weight average molecular weight) of the obtained polyimide (5) was 110,000. The molar ratio of acid component / amine component was 1.04.

  (6) Solution of polyimide (6) which is a reaction product of tetracarboxylic anhydride and diamine (non-volatile content: 26.2 wt%): synthesized in Synthesis Example 6 below.

(Synthesis Example 6)
In a reaction vessel equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction tube, 300.0 g of tetracarboxylic dianhydride (“BisDA-1000” manufactured by SABIC Japan LLC) and 665.5 g of cyclohexanone And the solution in the container was heated to 60 ° C. Then, 130.4 g of 4,4′-diamino-3,3′-dimethyldiphenylmethane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise. Thereafter, 121.0 g of methylcyclohexane and 423.5 g of ethylene glycol dimethyl ether were added, and an imidization reaction was performed at 140 ° C. for 16 hours to obtain a polyimide (6) solution (non-volatile content: 26.2% by weight). . The molecular weight (weight average molecular weight) of the obtained polyimide (6) was 20000. The molar ratio of acid component / amine component was 1.04.

  (7) A solution of polyimide (7) which is a reaction product of tetracarboxylic acid anhydride and diamine (non-volatile content: 22.5% by weight): synthesized in Synthesis Example 7 below.

(Synthesis Example 7)
In a reaction vessel equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction tube, 300.0 g of tetracarboxylic dianhydride (“BisDA-1000” manufactured by SABIC Japan LLC) and 665.5 g of cyclohexanone And the solution in the container was heated to 60 ° C. Then, 50.8 g of 1,4-diaminobutane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise. Thereafter, 121.0 g of methylcyclohexane and 423.5 g of ethylene glycol dimethyl ether were added, and an imidization reaction was performed at 140 ° C. for 16 hours to obtain a polyimide (7) solution (nonvolatile content: 22.5% by weight). . The molecular weight (weight average molecular weight) of the obtained polyimide (7) was 20000. The molar ratio of acid component / amine component was 1.04.

  (8) Solution of polyimide (8) which is a reaction product of tetracarboxylic anhydride and diamine (non-volatile content: 26.6% by weight): synthesized in Synthesis Example 8 below.

(Synthesis Example 8)
In a reaction vessel equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction tube, 300.0 g of tetracarboxylic dianhydride (“BisDA-1000” manufactured by SABIC Japan LLC) and 665.5 g of cyclohexanone And the solution in the container was heated to 60 ° C. Then, 137.4 g of 4,4′-methylenebis (2-methylcyclohexylamine) (manufactured by Tokyo Chemical Industry Co., Ltd., carbon number 15 of aliphatic structure) was added dropwise. Thereafter, 121.0 g of methylcyclohexane and 423.5 g of ethylene glycol dimethyl ether were added, and an imidization reaction was performed at 140 ° C. for 8 hours to obtain a polyimide (8) solution (nonvolatile content: 26.6% by weight). . The molecular weight (weight average molecular weight) of the obtained polyimide (8) was 10,000. The molar ratio of acid component / amine component was 1.04.

  (9) Solution of polyimide (9) which is a reaction product of tetracarboxylic acid anhydride and diamine (non-volatile content: 26.6% by weight): synthesized in Synthesis Example 9 below.

(Synthesis Example 9)
In a reaction vessel equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction tube, 300.0 g of tetracarboxylic dianhydride (“BisDA-1000” manufactured by SABIC Japan LLC) and 665.5 g of cyclohexanone And the solution in the container was heated to 60 ° C. Then, 137.4 g of 4,4′-methylenebis (2-methylcyclohexylamine) (manufactured by Tokyo Chemical Industry Co., Ltd., carbon number 15 of aliphatic structure) was added dropwise. Thereafter, 121.0 g of methylcyclohexane and 423.5 g of ethylene glycol dimethyl ether were added, and an imidization reaction was performed at 140 ° C. for 12 hours to obtain a polyimide (9) solution (nonvolatile content: 26.6% by weight). . The molecular weight (weight average molecular weight) of the obtained polyimide (9) was 60000. The molar ratio of acid component / amine component was 1.04.

  (10) Solution of siloxane skeleton-containing polyimide (10) (non-volatile content: 46.2 wt%): synthesized in Synthesis Example 10 below.

(Synthesis Example 10)
In a reaction vessel equipped with a stirrer, a water separator, a thermometer, and a nitrogen gas introduction tube, 53.00 g of 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride (“BTDA” manufactured by Daicel) and , 185.50 g of cyclohexanone and 37.10 g of methylcyclohexane were added, and the solution was heated to 60 ° C. Then, after gradually adding 139.17 g of α, ω-bis (3-aminopropyl) polydimethylsiloxane (“KF-8010” manufactured by Shin-Etsu Chemical Co., Ltd.), the solution was heated to 140 ° C. and taken for 1 hour. By performing the imidization reaction, a solution of polyimide (10) (non-volatile content: 46.2% by weight) was obtained. The molecular weight (weight average molecular weight) of the obtained polyimide (10) was 18000.

(Examples 1-10 and Comparative Examples 1-8)
The components shown in Tables 1 and 2 below were blended in the blending amounts shown in Tables 1 and 2 below, followed by stirring at 1200 rpm for 4 hours using a stirrer to obtain an interlayer insulating material (resin composition varnish).

  Using an applicator, an interlayer insulating material (resin composition varnish) obtained on the release treatment surface of a polyethylene terephthalate (PET) film (“XG284” manufactured by Toray Industries Inc., thickness 25 μm) was applied, and then 100 ° C. It was dried in a gear oven for 2.5 minutes to volatilize the solvent. Thus, a PET film and a resin film (B stage film) having a thickness of 40 μm on the PET film and a remaining amount of solvent of 1.0% by weight or more and 3.0% by weight or less. A laminated film having was obtained.

  Thereafter, the laminated film was heated at 190 ° C. for 90 minutes to produce a cured body in which the resin film was cured.

(Evaluation)
(1) State of sea-island structure A cross section of the obtained cured body was observed with a scanning electron microscope (SEM) at a magnification of 1500 times in a reflected electron mode, and the presence or absence of phase separation within 3200 μm ² was evaluated. Furthermore, when the sea-island structure exists, the major axis of each island part was measured from the observation image. The measured values were averaged to determine the average major axis of the islands. When the sea-island structure was observed, the average major axis of the island was determined according to the following criteria.

[Criteria for determining the major axis of the island (average major axis)]
○○: 3 μm or less ○: Over 3 μm, 5 μm or less ×: Over 5 μm

(2) Peel strength (90 ° peel strength)
Both sides of the CCL substrate ("E679FG" manufactured by Hitachi Chemical Co., Ltd.) on which the inner layer circuit is formed by etching are immersed in a copper surface roughening agent ("MEC etch bond CZ-8100" manufactured by MEC) to roughen the copper surface. Processed. The obtained laminated film was set on both surfaces of the CCL substrate from the resin film side, and laminated on both surfaces of the CCL substrate using a diaphragm type vacuum laminator (“MVLP-500” manufactured by Meiki Seisakusho Co., Ltd.) An uncured laminated sample A was obtained. Lamination was performed by reducing the pressure for 20 seconds to a pressure of 13 hPa or less, and then pressing for 20 seconds at 100 ° C. and a pressure of 0.8 MPa.

  In the uncured laminated sample A, the PET film was peeled from the resin film, and the resin film was cured at 180 ° C. for 30 minutes to obtain a cured laminated sample.

  The cured laminated sample is put into a swelling solution at 80 ° C. (an aqueous solution prepared from “Swelling Dip Securigant P” manufactured by Atotech Japan Co., Ltd.) and “Sodium hydroxide” manufactured by Wako Pure Chemical Industries, Ltd. Rock at 10 ° C. for 10 minutes. Thereafter, it was washed with pure water.

  Put the above laminated sample swollen into 80 ° C sodium permanganate roughening aqueous solution ("Concentrate Compact CP" manufactured by Atotech Japan, "Sodium hydroxide" manufactured by Wako Pure Chemical Industries, Ltd.), and roughening temperature Rocked at 80 ° C. for 30 minutes. Then, after washing | cleaning for 2 minutes with a 25 degreeC washing | cleaning liquid ("Reduction securigant P" by the Atotech Japan company, "Sulfuric acid" by Wako Pure Chemical Industries Ltd.), it wash | cleaned further with the pure water. In this way, a roughened cured product was formed on the CCL substrate on which the inner layer circuit was formed by etching.

  The surface of the roughened cured product was treated with a 60 ° C. alkali cleaner (“Cleaner Securigant 902” manufactured by Atotech Japan) for 5 minutes and degreased and washed. After washing, the cured product was treated with a 25 ° C. pre-dip solution (“Pre-Dip Neogant B” manufactured by Atotech Japan) for 2 minutes. Thereafter, the cured product was treated with an activator solution at 40 ° C. (“Activator Neo Gantt 834” manufactured by Atotech Japan) for 5 minutes to attach a palladium catalyst. Next, the cured product was treated with a reducing solution at 30 ° C. (“Reducer Neogant WA” manufactured by Atotech Japan) for 5 minutes.

  Next, the cured product is put into a chemical copper solution (all manufactured by Atotech Japan “Basic Print Gantt MSK-DK”, “Copper Print Gantt MSK”, “Stabilizer Print Gantt MSK”, “Reducer Cu”). Was carried out until the plating thickness reached about 0.5 μm. After the electroless plating, annealing was performed at a temperature of 120 ° C. for 30 minutes in order to remove the remaining hydrogen gas. All the steps up to the electroless plating step were performed with a treatment liquid of 2 L on a beaker scale and while the cured product was swung.

Next, electrolytic plating was performed on the cured product that had been subjected to electroless plating until the plating thickness reached 25 μm. As an electrolytic copper plating, a copper sulfate solution (“copper sulfate pentahydrate” manufactured by Wako Pure Chemical Industries, Ltd., “sulfuric acid” manufactured by Wako Pure Chemical Industries, Ltd., “basic leveler kaparaside HL” manufactured by Atotech Japan Co., Ltd., “ using the correction agent Cupracid GS "), plating thickness passing a current of 0.6 a / cm ² was carried out electrolytic plating until approximately 25 [mu] m. After the copper plating treatment, the cured product was heated at 190 ° C. for 90 minutes to further cure the cured product. Thus, the hardened | cured material with which the copper plating layer was laminated | stacked on the upper surface was obtained. At this time, the state of the sea-island structure in the cured product was the same as the state of the sea-island structure in the obtained cured body.

  In the cured product obtained by laminating the obtained copper plating layer, a 10 mm wide cutout was made on the surface of the copper plating layer. Then, using a tensile tester (“AG-5000B” manufactured by Shimadzu Corporation), the adhesive strength (90 °) between the cured product (insulating layer) and the metal layer (copper plating layer) under the condition of a crosshead speed of 5 mm / min. Peel strength) was measured. The peel strength was determined according to the following criteria.

[Peel strength criteria]
○○: Peel strength is 0.5 kgf / cm or more ○: Peel strength is 0.4 kgf / cm or more and less than 0.5 kgf / cm ×: Peel strength is less than 0.4 kgf / cm

(3) Dielectric loss tangent The obtained resin film was cut into a size of 2 mm in width and 80 mm in length, and five sheets were stacked to obtain a laminate having a thickness of 200 μm. The obtained laminate was heated at 190 ° C. for 90 minutes to obtain a cured body. About the obtained hardened | cured material, it uses a "cavity resonance perturbation method dielectric constant measuring device CP521" made by Kanto Electronics Application Development Co., Ltd. and "Network Analyzer N5224A PNA" made by Keysight Technology Co., Ltd. at room temperature (23 ° C) by the cavity resonance method. The dielectric loss tangent was measured at a frequency of 1.0 GHz.

(4) Desmearability (removability of residue at the bottom of the via)
Lamination and semi-curing treatment:
The obtained resin film was vacuum-laminated on a CCL substrate (“E679FG” manufactured by Hitachi Chemical Co., Ltd.) and heated at 180 ° C. for 30 minutes to be semi-cured. Thus, the laminated body A by which the semi-cured material of the resin film was laminated | stacked on the CCL board | substrate was obtained.

Via (through hole) formation:
Using a CO ₂ laser (manufactured by Hitachi Via Mechanics), a semi-cured product of the resin film of the obtained laminate A is a via having a diameter of 60 μm at the upper end and a diameter of 40 μm at the lower end (bottom) (through) Hole) was formed. Thus, the laminated body B by which the semi-cured material of the resin film was laminated | stacked on the CCL board | substrate, and the via | veer (through-hole) was formed in the semi-cured material of the resin film was obtained.

Removal of residue at the bottom of the via:
(A) Swelling treatment The obtained laminate B was placed in a swelling liquid at 80 ° C. (“Swelling dip securigant P” manufactured by Atotech Japan Co., Ltd.) and rocked for 10 minutes. Thereafter, it was washed with pure water.

(B) Permanganate treatment (roughening treatment and desmear treatment)
The layered product B after swelling treatment was placed in a roughened aqueous solution of potassium permanganate (“Concentrate Compact CP” manufactured by Atotech Japan Co., Ltd.) at 80 ° C. and rocked for 30 minutes. Next, the sample was treated for 2 minutes using a 25 ° C. cleaning solution (“Reduction Securigant P” manufactured by Atotech Japan), and then washed with pure water to obtain Evaluation Sample 1.

  The bottom of the via of evaluation sample 1 was observed with a scanning electron microscope (SEM), and the maximum smear length from the wall surface of the via bottom was measured. The removability of the residue at the bottom of the via was determined according to the following criteria.

[Judgment criteria for removal of via bottom residue]
○○: Maximum smear length is less than 2 μm ○: Maximum smear length is 2 μm or more and less than 3 μm ×: Maximum smear length is 3 μm or more

(5) Surface roughness (arithmetic mean roughness Ra)
The surface of the roughened cured product obtained by the evaluation of (2) 90 ° peel strength is 94 μm × 123 μm using a non-contact three-dimensional surface shape measuring device (“WYKO NT1100” manufactured by Veeco). Arithmetic mean roughness Ra was measured in the measurement region. The surface roughness was determined according to the following criteria.

[Surface roughness criteria]
○○: Ra is less than 50 nm ○: Ra is 50 nm or more and less than 200 nm ×: Ra is 200 nm or more

(6) Average linear expansion coefficient (CTE)
The obtained cured product (using a 40 μm thick resin film) was cut into a size of 3 mm × 25 mm. Using a thermomechanical analyzer (“EXSTAR TMA / SS6100” manufactured by SII Nano Technology), the cured product cut at 25 ° C. to 150 ° C. under conditions of a tensile load of 33 mN and a heating rate of 5 ° C./min. The average linear expansion coefficient (ppm / ° C.) was calculated. The average linear expansion coefficient was determined according to the following criteria.

[Judgment criteria for average linear expansion coefficient]
○○: Average linear expansion coefficient is 25 ppm / ° C. or less ○: Average linear expansion coefficient exceeds 25 ppm / ° C., 30 ppm / ° C. or less ×: Average linear expansion coefficient exceeds 30 ppm / ° C.

  The compositions and results are shown in Tables 1 and 2 below.

DESCRIPTION OF SYMBOLS 11 ... Multilayer substrate 12 ... Circuit board 12a ... Upper surface 13-16 ... Insulating layer 17 ... Metal layer

Claims (10)

It is a cured body of a resin composition containing an epoxy compound, a curing agent, an inorganic filler, and polyimide,
In 100% by weight of the cured body, the content of the inorganic filler is 30% by weight or more and 90% by weight or less,
The said hardening body has a sea island structure which has a sea part and an island part, the average major axis of the said island part is 5 micrometers or less, and the said island part contains the said polyimide.   The hardening body of Claim 1 whose content of the said polyimide is 3 weight% or more and 50 weight% or less in 100 weight% of components except the said inorganic filler in the said hardening body.   The hardened | cured material of Claim 1 or 2 in which the said hardening | curing agent contains an active ester compound.   The hardening body of any one of Claims 1-3 in which the said resin composition contains a hardening accelerator.   The hardened | cured material of any one of Claims 1-4 in which the said inorganic filler contains a silica.   The cured body according to claim 5, wherein the content of the silica is 40% by weight or more in 100% by weight of the cured body.   The cured body according to any one of claims 1 to 6, wherein the polyimide has an aliphatic structure having 6 or more carbon atoms.   The cured body according to any one of claims 1 to 7, wherein the polyimide is a polyimide excluding a polyimide having a siloxane skeleton.   A component in which the total content of the unreacted product of the epoxy compound and the reacted product of the epoxy compound in 100% by weight of the component excluding the inorganic filler in the cured product is a component excluding the inorganic filler in the cured product. The hardened | cured material of any one of Claims 1-8 which is more than content of the said polyimide in 100 weight%. A circuit board;
An insulating layer disposed on the circuit board,
The multilayer substrate whose material of the said insulating layer is the hardening body of any one of Claims 1-9.

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